Hydraulic valve tappet



Jan. 27, 1959 E. L. DAYTON 2,870,756

- HYDRAULIC VALVE TAPPET Filed July 13, 1956 FIG.I.

FIG.4.

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IN V EN TOR.

ERNEST L. DAYTON ATTORNEYS United States Patent "Ti ce HYDRAULIC VALVETAPPET Ernest L. Dayton, Detroit, Mich.

Application July 13, 1956, Serial No. 597,713

20 Claims. (Cl. 123-90) This invention relates to an improved hydraulicvalve tappet assembly of the type suitable for use in connection withinternal combustion engines.

Hydraulic tappet assemblies, as used in internal combustion engines, areusually supplied with oil from the lubricating system of the engine andfunction to take up clearance between the valve push rods and'tappetsautomatically as soon as such clearance exists. The specific structureof hydraulic valve tappets varies considerably but, in general,comprises a cylinder and a tubular plunger -or piston slidably supportedin the cylinder. When installed, the bottom of the cylinder is usuallyengaged by a cam on the camshaft of the engine and the top of the pistonis closed by a plug which ordinarily engages the valve operating pushrod.

Also, an adjusting chamber is normally provided in the cylinder belowthe piston and the bottom of the piston has a valve controlled portcommunicating with the adjusting chamber Hydraulic fluid, such as oil,is admitted to the adjusting chamber through the valve controlled portand the clearance between the piston and push rod is-taken up by thecolumn of oil below the piston. The port in the piston is controlled bya ball valve member which operates as a check valve and is held in placeadjacent the port by a suitable retainer. 'It is important to thesatisfactory operation of the tappet assembly to limit the clearancebetween the ball valve member and the valve seat surrounding the port toprecise tolerances. Moreover, it is extremely desirable to form theretainer so that it is readily adjustable to obtain the desired limit ofclearance between the ball valve member and its seat. Accordingly, oneobject of this invention is to provide a retainer which is readilyadjustable.

Another object of the invention is to provide a retainer for the valvemember which includes an adjustable valve retaining bar which extendsacross the side of the'valve member opposite the valve seat, theretainer being formed to provide sufiicient clearance to permit thelateral insertion of a feeler gauge between the bar and the valve memberduring adjustment of the bar and when the valve member is seated againstthe seat. I

Still another object of the invention is to provide a retainer for thevalve member as described in the preceding paragraph in which theretainer is formed to provide clearance at the side of the bar oppositethe valve member to enable striking the aforesaid side of the bar a blowto effect the necessary adjustment of the bar.

2,870,756 Patented Jan. 27,1959

Figure 4 is a fragmentary sectional view showing a .modification.

Figure-5 is a plan view of the valve retainer shown in Figure 4.

Figure 6 is similar to Figure 4 and shows still another modification.

Figure 7 is a bottom view of the piston shown in Figure 4.

Referring now more particularly to the drawings and especially toFigures 13, the numeral 10 indicates a part of an internal combustionengine and the numeral 11 designates a hydraulic valve tappet assemblyembodying the invention. The tappet assembly comprises a cylinder 12 anda piston 13 supported within the cylinder for longitudinal slidingmovement. The cylinder 12 is, in turn, slidably mounted in a bore 14formed in the part 10 of the engine and the bottom of the cylinder isclosed by a wall 15. The bottom surface of. the wall 15 forms a bearingfor engagement with a cam 16 forming a part of the usual engine camshaft(not shown). The top of the cylinder 12 is open for receiving a push rod17 which is operatively connected to one valve of the engine in a mannerforming no part of this invention and, hence, not shown herein.

The piston 13 is tubular in cross section and the top of the piston isclosed by a cap 18 which is securely fixed to the piston. In the presentinstance, the cap 18 has a restricted vent 19 therethrough and has areduced part 20 which is externally threaded for threaded engagementwith the internal threads formed in the upper end of the piston. The topof the cap has a hemispherical recess 21v for pivotally engaging acorresponding hemispherical portion at the lower end of the push rod 17.The arrangement is such that the hydraulic tappet assembly provides aconnection between the cam 16 and push rod 17 for operating the push rodin response to rotation of the cam.

The internal diameter of the cylinder'12' is reduced at the bottom toprovide an adjusting chamber or oil reservoir 22 and also to provide aninternal annular shoulder 23 for engaging the bottom of the piston inthe leak-down or collapsed position of the piston within the cylinder.As illustrated in Figure 1, the piston 13 is shown in its extendedposition.

As shown in Figure 1, the bottom of the piston ha a port 24 whichestablishes communication between the adjusting chamber 22 and the spaceor chamber 25 within the piston. The transfer of oil through the port 24is controlled by a ball check valve 26 at the bottom of piston 13. Thecheck valve 26 comprises a ball member 27, a retainer 28 and a coilspring 29.

Other objects and features of the invention will become apparent as thedescription proceeds, especially when taken in conjunction with theaccompanying drawings, wherein:

Figure 3 is a fragmentary sectional view showing the method employed inadjusting the check valve.

The ball member 27 is of a diameter to engage an annual seat 30surrounding the port 24 at the bottom of the piston and the retainer 28holds the ball in a manner to enable movement of the ball to its openposition. The retainer 28 is of one-piece construction and is in theform of a cylindrical tubular sheet metal member extending around theball in coaxial relationship to the piston 13. The upper end of thetubular retainer 28 is turned radially outwardly to provide a flange 31engageable with the underside of the piston 13. The upper end of thetubular retainer closely receives the tubular extension 31 at the lowerend of the piston which surrounds the port 24. A

-washer 32' surrounds the tubular retainer and is engaged and pressedagainst flange 31 by the upper end of the spring 29 which has its lowerend seated on the bottom wall 15 of the cylinder. The coil spring 29 isheld under compression between the washer 32' and wall 15 and is ofsufiicient strength to hold the retainer 28 in place on the piston 13throughout the movement of the latter between its collapsed and extendedpositions. The coil spring 29 also tends to maintain the piston 13 inits extended posi-- assume tion relative to the cylinder during normaloperation of the tappet but is not of sufiicient strength to preventmovement of the cylinder 13 to its collapsed or leak-down position inwhich the lower end thereof engages the shoulder 23, when operation ofthe engine is discontinued. When the cylinder 12 rotates (as it oftendoes because of an off center engagement with cam 16), and rotates thespring 29 and washer 32, the retainer 28 will not rotate because of thestronger frictional contact between the piston and Washer than betweenthe flange 31 and washer. This stronger frictional contact results fromthe fact that the area of contact between washer 32 and flange 31 issubstantially less than that between flange 31 and the piston,coefficients of friction for the parts being about the same. Thus thereis no wear on eitherthe piston or flange 31 where they contact and henceno disturbance of the adjustment of the retainer.

The ball member 27 is held in assembledrelation with the retainer 28 bya cross bar 32 integrally connecting opposite sides of the tubularretainer below the ball 27. As seen in the drawings, the major portionof the bar 32 is disposed at right angles to the axis of the cylindricalwall of the retainer and is spaced below the lower margin thereof, suchlower margin being disposed entirely in a plane at right angles to thelongitudinal axis of the retainer. The opposite ends of the bar areturned upwardly extending parallel to the retainer axis and integrallyconnect into the tubular portion of the retainer at diametricallyopposite sides thereof. as consistent with good stamping practice and,in any case, does not restrict the flow of oil through the retainer. Thefree flow of oil through the retainer 28 is important because it assistsin filling the space below the piston 13 in the leak-down position ofthe tappet and also exposes a greater area of the ball 27 to the oil insaid space to assure instantaneous closing of the ball against its seat.

The axial spacing between the bar 32 and seat 30 is accuratelypredetermined with the respect to the diameter of the ball member 27 Inpractice, the bar 32 is located.

to afiord a predetermined maximum clearance between the seat 30 and ball27 in the open position of the latter. With a retainer constructed inaccordance with the foregoing, proper positioning of the bar 32 may beaccomplished readily by inserting a feeler gauge 33 between the ball 27and bar 32, and thereafter adjusting the bar 32 until the ball 27 isfirmly engaged with the seat 30. It will be appreciated that sincesubstantially the entire length of the bar 32 is below the tubularportion of the retainer 28, suflicient lateral clearance is alforded topermit the. lateral insertion of the feeler gauge. After the feelergauge is inserted, the adjustment may be accom plished by striking thelower side of the bar 32 a blow and the bar, which is deformable, willbe deformed under the impact of the blow to the desired position ofadjustment. It might be pointed out that the retainer is formed of amaterial having very little resilience so that this adjustment of thebar may be accomplished as described. Thus, the adjustment of theretainer is accomplished quickly and easily. Since no wear takes placebetween the retainer flange 31 and the piston, the adjustment willremain indefinitely. The feeler gauge may be readily inserted. This isbecause the relatively narrow width of cylinder wall and the dischargeside opens into an annular groove 37 formed in the outer surface of thepiston. The

The bar 32 is as narrow the bar leaves practically of are at either sideof t the bar through which the feeler gauge may be inserted. Theretainer may be inexpensively manufactured and readily adjusted. This isin sharp contrast to conventionalitappets which are not adjustable andin which the annular groove 36 is of suflicient width to register withthe supply passage 34 through the stroke of the cylinder within the bore14. In the normal operation of the hy draulic tappet assembly, thegroove 37 communicates with the chamber 25 in the piston 13 through aport 38 formed'in the adjacent wall of the piston and the width of thegroove 37 is sufficient to register with the port 38 throughout the fullstroke of the piston relative to the cylinder.

The hydraulic tappet assembly is shown in it's normal operating positionin Figure 1 wherein it will be noted that the bottom of the piston isspaced above the shoulder I 23, and a column of oil is provided betweenthe lower end of the piston and the bottom wall 15 of the cylinder. Thiscolumn of oil takes up the clearance between the pushrod 17 and enginevalve mechanism affording quiet operation of the latter. The port 38meters fluid into the chamber 25 in the piston, and the oil thusadmitted. to the chamber 25 is maintained inthe latter until thepressure below piston 13 drops sufliciently to enable movement of theball member 27 away from its seat whereupon oil from the chamber 25flows through port 24 into the cylinder below the piston. Owing to thefact that the bar 32 is very narrow, generous passages are provided atopposite sides of the bar with the result that ample oil is available inthe retainer to replenish the space below the piston in the openposition of the ball member 27, and with the added result that the ballmember 27 is more readily responsive to an increase of pressure in thespace below the piston. In other words, the ball member 27 will closepractically instantaneously upon an increase in pressure in chamber 22.Hence, there is no apparent lost motion of the parts and objectionableclearance in the engine valve operating mechanism is avoided.

The reduction of lost motion is also assisted by fixing the cap 18securely to the top of the piston in a manner such that displacement ofthe cap by lubricant under pressure in chamber 25 is prevented. It willbe ap; parent that if lost motion is present in the valve op eratingmechanism and the cap 18' is not securelyfixed to the piston, thepressure in the chamber 25 may simply lift the cap to take up theclearance in the valve operating mechanism without being exerted againstthe ball member 27 with suflicient force to unseat it. By securelyfastening the cap 18 to the piston, the full effect of the oil pressurewithin chamber 25' is applied tothe valve member 27 to open-the same forreplenishing chamber 22 and in such manner taking up the clearance inthe valve operating mechanism.

The cap 18 has an integral extension in the form of a sleeve 45 looselysurrounding the push rod. The sleeve has an annular enlargement orflange 46. at the upper end, and a washer 47 loosely encircles thesleeve and overlies the vents 19. These vents are normally closed by thewasher which is pressed down against the cap 18 by a compressioncoilspring 48 also encircling the sleeve. The upper end of the spring bearsagainst the flange 46 and the lower end'bears against the washer.Normally the vents are closed by the washer during the action describedin the preceding paragraph. However, the spring has a forcepredetermined to allow the washer to raise'or' open when thepressure'inthe piston chamber exceeds a certain maximum amount, thispressure acting on the washer through the vents. 19. Thus the washer isa' relief valve to relieve excessive pressure on the piston chamberthrough vents 19.

Figure 4 illustrates amodified construction in which parts correspondingto those shown' in Figures 1-3 are identified by the same referencenumerals. The'Figure 4 construction differs from that previouslydescribed'p'rima'rily in'the construction of the retainer hereindesignated by the'reference numeral 50. The 'port 24'als'o has a lowerportion 49 of enlarged diameter. The retainer 50 is generally in theform of a one-piece flat ring having tabs 51 cut at diametricallyopposite sides, formed by the generally radial slits 52. These tabs fitinto tapered recesses at diametrically opposite sides of the piston toprevent the retainer from rotating when pressed up against the bottom ofthe piston. The recesses are of about the same circumferential extent orwidth as the tabs so that the tabs are closely confined by oppositesides of the recesses to prevent rotation. The central opening in theretainer has radial slits defining a plurality of fingers, alternatefingers 53 being turned axially upwardly into the enlarged portion 49 ofport 24 to center the retainer, and the remaining fingers 54 beingturned axially downwardly into the upper end of spring 29 to center thespring. The lower end of spring 29 is, of course, compressed against thebottom of the cylinder and presses the retainer tightly against thepiston.

The-ball member 27 is held in assembled relation with the retainer 50and prevented from dropping through the opening in the retainer bya bar60 which is integrally connected to the inner margin of the openingthrough the retainer. The bar 60 has a portion 61 which extends parallelto the axis of the retainer and a terminal portion 62 which extends atright angles to the axis. The bar is sufficiently narrow. so that itdoes not restrict the flow of oil through the retainer. The axialspacing between the bar 60 and the seat 30 is accurately predeterminedwith respect to the diameter of the ball 27. In practice, thepredetermined maximum clearance between the seat 30 and the ball 27 isprovided by adjusting the deformable practically non-resilient bar 60 ina manner similar to the adjustment of the bar 32 in the firstembodiment. That is, a feeler gauge, such as the gauge 33, is insertedbetween the ball and the portion 62 of bar 60 when the ball is seatedagainst seat 30, and the portion '62 may be struck a blow to deform itagainst the feeler gauge. One advantage of this retainer constructionover that first described is that the bar 60 is connected to the annularportion of the retainer at one end only, thereby increasing the angularpositions from which the feeler gauge may be laterally inserted betweenthe ball and the bar to effect an adjustment.

Figure 6 shows still another modification in which parts similar tothose described in connection with the first two embodiments areidentified by the same characters of reference. In this construction,the piston 113 differs from the piston 13 in that the port 124 has anupper portion 125 of reduced diameter and a lower portion 126 ofenlarged diameter separated by an annular shoulder 127. The ball 27seats against the annular corner between the shoulder 127 and theportion of the port of reduced diameter.

The retainer 70 is in the form of an L-shaped member of a materialhaving little resilience, one leg of which extends up into a hole in thetubular extension 31' and is securely held in place therein. The otherleg 72 extends transversely of the cylinder across the lower end of thepiston and is provided to retain the ball 27 in place within theenlarged diameter portion of port 124. The predetermined maximum spacingbetween the ball 27 and its .seat is determined by adjusting thetransverse leg 72 of the retainer. The leg 72 is adjusted by deformingthe same and this is accomplished in the same way as described inconnection with the previous embodiments. That is, a feeler gauge, suchas gauge 33, is inserted between the leg 72 and the ball and then a blowis struck against the leg 72 to bend or deform it tightly against thefeeler gauge. Since the retainer 70 is secured at only one end, thefeeler gauge may be inserted very easily from almost any angle. Theextension 31 has diametrically opposite depending parts 75, only one ofwhich appears, these parts being disposed on opposite sides of the portand retainer and extending beneath the 6 retainer for engagement withthe bottom of the cylinder" in the leak-down position of the device.

What I claim as my invention is:

l. A hydraulic valve tappet assembly comprising a cylinder having oneend closed and having a chamber at the closed end thereof, a pistonslidably supported in said cylinder and having a chamber therein a portin the end of said piston adjacent the closed end of said cylinderproviding communication between said chambers, a seat surrounding saidport, a valve member supported in a position to engage said seat, aretainer for said valve member carried by said piston and having anadjustable bar positioned to engage the side of said valve memberopposite said seat, said retainer being formed to provide sufficientlateral clearance to permit the lateral insertion of a feeler gaugebetween said valve member and bar during adjustment of said bar whensaid valve member is seated against said seat.

2. A hydraulic valve tappet assembly .as defined in claim 1, in whichsaid bar is deformable and is adjusted by deforming the same.

3. A hydraulic valve tappet assembly as defined in claim 2, in whichsaid retainer is formed to provide clearance at the side thereofopposite said valve member to permit deforming said bar by striking ablow against the aforesaid side thereof while said feeler gauge isinserted as aforesaid.

4. A hydraulic valve tappet assembly comprising a cylinder having oneend closed and having a chamber at the closed end thereof, a pistonslidably supported in said cylinder and having a chamber therein, a portin the end of said piston adjacent the closed end of said cylinderproviding communication between said chambers, a seat surrounding saidport, a ball valve member supported in I a position to engage said seat,a retainer for said ball valve member carried by said piston and havingan annular wall encircling said ball valve member and extending awayfrom said seat, the end of said annular wall remote from said seat beingopen, an adjustable bar,

. extending at least part way across said open end and having at leastone end connected to said annular wall, said bar being spaced beyond theremote end of said annular wall to provide sufiicient clearance topermit the lateral insertion of a feeler gauge between said ball valvemember and bar during adjustment of said bar when said ball valve memberis seated against said seat.

5. A hydraulic valve tappet assembly as defined in claim 4 in which saidbar is deformable and is adjusted by deforming the same.

6. A hydraulic valve tappet assembly as defined in claim 5 in which saidretainer is formed to provide clearance at the side of said bar remotefrom said ball valve member to permit deforming said bar by striking ablow against the aforesaid side thereof while said feeler gauge isinserted as aforesaid.

7. A hydraulic valve tappet assembly as defined in claim 6 in which bothends of said bar are connected to, said annular wall at opposite sidesthereof.

8. A hydraulic valve tappet assembly as defined in claim 7 in which saidretainer has an annular flange en.- circling said seat, one side of saidflange frictionally engaging said end of said piston, a washerfrictionally engaging the opposite side of said flange, and a springcompressed between said washer and the closed end of said cylinder, thefrictional contact between said washer and flange being less than thatbetween said flange and piston so that any rotation imparted to saidwasher by said spring will not induce rotation of said retainer.

9. A hydraulic valve tappet as defined in claim 8 in which the area ofcontact between said washer and flange is less than that between saidflange and piston.

10. A hydraulic valve tappet assembly comprising a cylinder having oneend closed and having a chamber at the closed end thereof, a pistonslidably supported in said cylinder and having a chamber therein, a portin the aeratedported in a position to engage said seat, a retainer forsaid ball valve member carried by said piston and comprising anadjustable bar of deformable, relatively nonresilient materialpositioned to engage the side of said ball valve member opposite saidseat,'said retainer being secured directly to said end of said pistonand having a part spaced from said end of'said piston to providesufficient lateral clearance to permit the lateral insertion of a feelergauge between said ball valve member and part during adjustment of saidbar-when said ball valve member is seated against said seat.

11. A hydraulic valve tappet assembly comprising a cylinder having oneend closed andhaving a chamber at the closed end thereof, a pistonslidably supported in said cylinder and having a chamber therein, a portin the end of said piston adjacent the closed end of said cylinderproviding communication between said chambers, a seat surrounding saidport, a ball valve member supported in a position to engage said seat, aretainer for said ball valve member carried by said piston andcomprising an adjustable bar of deformable, relatively non-resilientmaterial positioned to engage the side of said ball valve memberopposite said seat, said bar being generally Lshaped having one legsecured directly to said end of said piston and the other leg spacedfrom said end of said piston to provide sufficient lateral clearance topermit the lateral insertion of a feeler gauge between said ball valvemember and said other leg during adjustment of said bar when said ballvalve member is adjusted against said seat.

12. A hydraulic valve tappet assembly as defined in claim 11. in whichsaid bar is deformable and is adjusted by being deformed. 7

13. A hydraulic valve tappet assembly as defined in claim 12 in whichsaid retainer is formed to provide clearance at the side of said one legremote from said ball valve member to permit deforming said one leg bystriking a blow against the aforesaid side thereof while said feelergauge is inserted as aforesaid.

14. A hydraulic valve tappet assembly comprising a cylinder having aclosed end and having a chamber at the closed end thereof, a pistonsupported in said cylinder for sliding movement from a collapsedposition adjacent the closed end of said cylinder to an extendedposition more remote from said closed end, said piston having a chambertherein communicating with the chamber in said cylinder through a portin the end of said piston adjacent the closed end of said cylinder,valve means controlling communication through said port, an inlet portin one side of said cylinder, porting in said piston arranged to connectsaid inlet port to said chamber in said piston in all positions ofsaidpiston relative to said cylinder, said piston having a head at theopposite end thereof closing said chamber in said piston which is arigid part of said piston and movable as a unit therewith, and a pushrod extending into the opposite end of said cylinder and engageable withsaid head.

15. A hydraulic valve tappet assembly as defined in claim" 14, said"head having.

said vent' when th'e'pressure in said chamber exceeds a predeterminedm'a'ximum.-

16. A hydraulic valve tappet assembly comprising a cylinder havingson'eend closed and having a chamber at'the' closed end thereof, a pistonslidably supported in said cylinder and'h'avin'g a chamber therein, aport in the eiid'of said piston adjacent the closedend of said cylinderproviding communication between said chambers, a-s'eat surrounding saidport, a ball valve member supported in a position to engage said seat, aretainer for said ball valve member carried by saidend' of said piston,said retainer being generally of ring shape and encircling said seat, anadjustable bar extending part way across the opening in said retainerand having one end connected to" the radially inner margin of saidretainer, the major portion" of said bar being spaced from saidretainertoward the closedend of said cylinder'to provide sufficient clearancefor the lateral insertion of a feeler gauge between said ball valvemember and. bar'duringadjust'ment of said bar when said ball valvemember is seated against said seat.

17. A hydraulic valve tappet assembly as defined in claiml6in'whichvsaid bar is deformable and is adjusted by deformingthe same.

18'. A hydraulic valve tappet assembly as defined in claim 17 in whichsaid retainer has tabs extending into c'ircumferentially spaced recessesin said end of said piston to prevent relative rotation between saidpiston and retainer.

191 A hydraulic tappet assembly for a valve comprising a cylinder closedat one end to provide a chamber for hydraulic fluid, a piston mounted insaid cylinder for longitudinal sliding movement between a collapsed position adjacent the closed end of said cylinder and an extended positionspaced axially from the closed end of said cylinder, a passage" in saidpiston, a port in the end of said piston; adjacent the closed end ofsaid cylinder connecting s'aidpassag'e and chamber, means for supplyinghydraulic fluid to said passage, valve means controlling the flow ofhydraulic fluid through said port including an annular seat surroundingsaid port at the side thereof facing the closed end of said cylinder, aball member supported in a position to engage said seat in response toan increase in pressure in said chamber, and a retainer for said ballmember including a bar extending across said ball member at the side ofthe latter away from said port and attached at least at one end formovement as a unit with said piston.

20. The tappet assembly defined in claim 19 in which one end only ofsaid bar is attached to further avoid interference during insertion of afeeler gage, said one end being rigidly attached directly to saidpiston,

References Cited in the file of this patent UNITED STATES PATENTS2,682,865 Voorhies July 6, 1954 2,755,785 Oldberg July 24, 19562,761,435 Oldberg Sept. 4, 1956 a vent therein, and a relief" valveno'rniall'y.- closin'gis'aid v'e'nt'an'd' adapted to open

